It has long been recognized that heat losses from a building are usually the most severe per unit area of external surface thereof through the windows and through the doors. Such heat losses have long been substantially reduced by use of storm windows or storm doors in connection with the windows and small doors of such building but the problem has continued to exist with respect to large doors. Where only a few doors have existed in a building, the heat losses therethrough have normally been tolerated. However, in buildings such as warehouses, aircraft hangars, garages, boat storage buildings and others of similar nature where the doors are large, they have often been the source of heat losses which have been significant. These losses have been particularly severe where, as is often the case, such doors are made of steel or other materials of good heat transmitting capabilities. In the case of sliding doors, such heat loss has sometimes been reduced by providing doors having multiple, as two, spaced panels and in some cases the space between such panels has been filled with insulation. However, where such doors have been of the roll type, and made of hingedly interlocking parallel strips of steel, such techniques have not been available. Some attempts have been made to spray insulation onto the slats of roll-type doors but the structural requirements of such doors have prevented good results. Hence, with roll-type doors, the heat losses have been severe.
Accordingly, the objects of the invention include:
1. To provide a door construction for utilizing solar radiation to minimize heat losses from within the building through such door.
2. To provide a door construction, as aforesaid, which is particularly adaptable to flexible roll-type steel doors.
3. To provide a door construction, as aforesaid, which will not materially change the general construction of the steel portion of the door and thereby not alter presently known and accepted specifications for roll-type steel doors.
4. To provide a door construction, as aforesaid, which will not materially, if at all, change the manner of operation of the door from that presently familiar for roll-type steel doors.
5. To provide a door construction, as aforesaid, which will not add materially to the cost of presently known roll-type steel doors.
6. To provide a door construction, as aforesaid, which will be durable and consequently long lasting but which if replacement is required, such replacement can be accomplished easily and quickly.
7. To provide a door construction, as aforesaid, which is easily and effectively sealed against passage of other than inconsequential amounts of air, if any, past such door into or out from the building with which such door is used.
8. To provide a door construction, as aforesaid, wherein the heat protective means can be readily applied to an existing roll-type door unit if desired and without the necessity for applying weather stripping to the original door.
Other objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspection of the accompanying drawings.